On screen
Cast
30 credited performers
Alec Guinness
Professor Marcus
Cecil Parker
Claude, alias 'Major Courtney'
Herbert Lom
Louis, alias 'Mr. Harvey'
Peter Sellers
Harry, alias 'Mr. Robinson'
Danny Green
'One-Round', alias 'Mr. Lawson'
Katie Johnson
Mrs. Wilberforce
Jack Warner
The Superintendent
Artwork unavailable
Philip Stainton
The Sergeant
Frankie Howerd
The Barrow Boy
Artwork unavailable
Madge Brindley
Large Lady (uncredited)
Artwork unavailable
Hélène Burls
Hypatia (uncredited)
Kenneth Connor
Cab Driver (uncredited)
Artwork unavailable
Michael Corcoran
Burglar (uncredited)
Harold Goodwin
Parcels Clerk (uncredited)
Fred Griffiths
Junk Man (uncredited)
Lucy Griffiths
Miss Pringle (uncredited)
Artwork unavailable
George Hilsdon
Security Van Driver (uncredited)
Artwork unavailable
Vincent Holman
Station Master (uncredited)
Stratford Johns
Security Guard (uncredited)
Sam Kydd
Second Cab Driver (uncredited)
Edie Martin
Lettice (uncredited)
Jack Melford
Detective (uncredited)
Arthur Mullard
(uncredited)
Ewan Roberts
Constable (uncredited)
Artwork unavailable
George Roderick
Radio Car Policeman (uncredited)
Artwork unavailable
John Rudling
Nervous Man (uncredited)
Artwork unavailable
Leonard Sharp
Pavement Artist (uncredited)
Peter Williams
Detective at Parcels Office (uncredited)
Neil Wilson
Policeman (uncredited)
Artwork unavailable
Phoebe Hodgson
Constance (uncredited)